This invention relates to approach tables for conveying articles of manufacture during their production wherein defective or inoperative table rollers can be taken out of service for repair or replacement without interruption of a production line. More particularly, the invention includes a roller mounting system having a split frame wherein part of the frame can move relative to the remainder of the frame to displace the roller from an operating position to an inactive or retracted position.
Approach tables are used to convey metal articles of manufacture such as slabs, blooms or billets from a caster to roughing or reducing mills wherein the articles are reduced in thickness and/or width. Approach tables also are used to convey articles to further processing equipment such as shears, finishing mills, strip coilers, and the like. An approach table includes a series of rollers for supporting an article as it is moved between various processing stations. Many of these rollers, such as rollers in a high speed runout table after a strip finishing mill, are driven by individual variable speed AC or DC electric motors with the speed of the motor being synchronized to the speed of the strip exiting from the last stand of the finishing mill.
Whenever an outer surface of a roller becomes defective or the roller becomes inoperative, the roller needs to be removed from the approach table for repair. For example, the roller may become inoperative because it has become broken, a roller bearing becomes locked, an electrical failure has occurred, a drive motor has failed, and the like. This defective equipment can not be removed, however, until a scheduled downturn occurs in the rolling mill because the frame for mounting each roller is rigidly connected to the roller table. In the meantime while the defective approach or roller table continues to be operated, a damaged outer surface of a defective roller or a non-rotating roller may cause surface defects to the article being conveyed along the production line.
Additional disadvantages of using rigidly mounted rollers in an approach table are the entire unit, including the roller support, must be removed during repair or replacement. This equipment removal not only is time consuming but also ties up maintenance personnel and equipment, e.g., an overhead crane, that otherwise could be used for maintenance elsewhere during the downturn.
Accordingly, there is a need to displace or remove a defective or inoperative roller from a roller table during the production of articles of manufacture without interruption of a production line.